2025MNRAS.540L..28K

In this Letter, we shed light on the evolutionary phase of HD 144812, a Galactic yellow supergiant showing infrared excess that is typically expected for evolved stars undergoing enhanced mass-loss activity. We present high-resolution spectroscopy of the star in the $H-$ and $K-$band acquired with the GRating INfrared Spectrometer (IGRINS) and further explore multiband imaging of the wider field of view from the ultraviolet to the radio regime. The IGRINS data reveal several lines from the hydrogen series and iron in a double-peaked emission and we here suggest that HD 144812 is orbited by a disc-hosting companion. Furthermore, we report emission in the CO band heads of the star that is modelled to arise from a circumstellar/binary disc (or ring) of ejected gas. The latter consists of material that is expected to have been dredged up from the core of the star to its surface during a prior phase as a red supergiant (RSG). These findings together suggest that HD 144812 is a rare, post-RSG star in a binary system, encouraging further investigation on the effect that the stellar encounters have on triggering instabilities and driving the evolution of the primary star shortly prior to the supernova event.